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Biomedical subjects

S Suga

Publications and source records attributed to S Suga.

At least 289 records · Page 16Linked to original sources
PubMed1990

[Disturbed formation of dental hard tissues after cyclophosphamide administration].

The changes appeared in the developing dentin and enamel of rat upper incisor after single intraperiotoneal injection of cyclophosphamide (4-8mg/100g body weight) were investigated histologically and microradiographically. 1) Changes appeared immediately after the injection were karyolysis, necrosis and intercellular accumulation of tissue fluid in the preodontoblast layer at the cell proliferating stage and its neighboring pulp tissue, however, no particular change was observed in the adjacent inner enamel epithelium cells. Those changes were more prominent in the labial side than the lingual side and expanded their range with time after the injection and then were replaced gradually by the fibroblasts proliferated. 2) Changes appeared in the dentin secondarily were as follows: a. Hypoplasia of dentin made by the odontoblasts which were at the stage of cell differentiation at the time of the injection. This is probably due to early cessation of dentinoplastic activity. b. Hypoplasia of the dentin induced by the odontoblasts which were at the stage of cell proliferation at the time of the injection. This change was induced by odontoblasts recovered from the changes described in 1). c. Hypomineralization appeared in the dentin which places more incisally than the site of change a and have commenced its matrix formation after the injection. This change did not accompany hypoplasia. d. Slight hypoplasia appeared at the basal side of change b. This change was made by the odontoblasts proliferated after the injection. With time after the injection, "niche" formation became observable at the pulpal surface of dentin due to hypoplasias mentioned above. 3) Osteodentin formation became appear secondarily and expanded its range in the pulp adjacent to the portion of the changes described in 2). Early cessation of dentin described in b and c of 2) is due to cell dysfunction occurred by pressure induced by osteodentin formation. 4) At the developing enamel adjacent to the hypoplastic dentin, no particular change was observed in the progressive mineralization pattern, although distortion of contour of surface or slight hypoplasia were observed.

Animals↗
PubMed1990

[Microradiographic investigations of carious changes in the enamel in the ground sections made perpendicularly to tooth axis].

Carious changes in the enamel in the undermineralized ground sections made perpendicularly to tooth axis were investigated using microradiography. By this way, relationship between carious invasion and the enamel lamellae and tuft, which has been not able to be examined in the longitudinal ground sections, could be clarified. 1) Direction of progress of demineralization and contour of demineralization front in the enamel are closely related to arrangement of enamel prisms. This findings strongly suggest that carious demineralization progresses along the enamel prisms. 2) Mode of carious demineralization in the enamel lamellae can be divided into two types; in the first type, demineralization progresses through the enamel lamellae more quickly than in the surrounding enamel and, in the second type, the enamel lamellae and its surrounding enamel show higher mineralization degree than the demineralized part in the rest of enamel, probably due to remineralization. The second type is observed more frequently than the first. 3) Mode of carious demineralization in the enamel tuft are also divided into two types; the first type which shows that demineralization progresses more quickly through the enamel tuft than the surrounding enamel and the second type that the enamel tuft and its surrounding narrow enamel are highly mineralized probably due to remineralization, whereas the rest of enamel is prominently demineralized. The second type is more frequently observed than the first. 4) In the ground sections made perpendicularly to tooth axis, it is more clearly observed that the interprismatic area is very highly remineralized whereas the main body of prism is easily demineralized, than in the longitudinal ground sections. 5) Striae of Retzius is composed of the band which appear to resist to demineralization and that which is easily demineralized. However, in the later case, demineralization which progresses laterally along the band can not be observed. 6) The degree and width of hypermineralized layer appeared in sound enamel along the demineralization front seem to be related to the rate of demineralization and arrangement of enamel prisms.

Dental Caries↗
PubMed1990

[SEM investigations on the human sclerosed dentinal tubules].

Sclerotic changes of dentinal tubules appeared in the dentin beneath the carious, attrition and abrasion lesions and in the transparent root dentin were investigated using the scanning electron microscopy. 1) Shape of crystal-like substances appeared in the dentinal tubules could not be closely related to kinds of dentin destruction. 2) In the dentinal tubules beneath the carious lesions, cuboidal or rhomboid-shaped, short rod-like, long rod-like, plate-like and droplet-like crystals were mainly observed. Combination of cuboidal or rhomboid-shaped and short rod-like crystals or that of long rod-like and plate-like crystals were most frequently observed. 3) In the dentinal tubules beneath attrition and abrasion lesions, cuboidal or rhomboid-shaped, short rod-like and droplet-like crystals were mainly observed, however, the size of cuboidal or rhomboid-shaped crystal was usually smaller than that observed beneath carious lesion and they deposited compactly within the tubules. 4) In the sclerosed dentinal tubules in the transparent root dentin, compact deposition of rhomboid-shaped and irregular sand-like crystals were usually observed. Size of rhomboid-shaped crystal is smaller than that observed beneath carious lesion. The deposit of sand-like crystal in the tubules was easily discriminated from the matrix of peritubular dentin. 5) In any case, the kinds of crystals and pattern of deposition were not necessarily same between the neighboring tubules. However, in a tubule, they were almost same in shape and mode of deposition throughout the entire length of tubule from the outer side to the pulpal side. These facts seem to indicate that mineral deposition within the tubule due to sclerosis is performed under individual condition. 6) Finding showing biological control of mineral deposition within the dentinal tubules by the odontoblasts could not be observed.

Calcinosis↗
PubMed1990

Effect of glycerol on ischemic edema evaluated by somatosensory evoked potentials.

Glycerol is administered to reduce intracranial pressure by clinically enhancing cerebral edema. In this study, the effect of glycerol on ischemic edema was evaluated in 34 cerebral infarct patients by serial SEP. Evoked potentials were obtained by stimulating the hemiparetic median nerve 60 times with duration of 0.1 msec. N20 wave of SEP was analyzed by signal processor. SEP was monitored every 30 min for 3 hr after glycerol administration. Improvements of CCT, which means interpeak latency between N13 and N20, were observed in 14 patients. In seven patients, N20 waves were observed after IV administration of glycerol even though N20 waves were not observed before glycerol administration. The patients in acute stage or with the small infarction of basal ganglia showed these electrophysiological improvements. No CCT changes were observed in nine patients, and no N20 waves were obtained in two patients even after glycerol administration. In conclusion, electrophysiologically, glycerol effect on ischemic edema was well recognized in acute staged infarct patients and the patients with small infarction of basal ganglia.

Aged↗
PubMed1989

Detection and characterization of endothelin-1-like immunoreactivity in rat plasma.

Using two radioimmunoassays (RIAs) for endothelin-1 (ET-1) with and without a substantial cross-reactivity with ET-3, we have measured the plasma ET-1-like immunoreactivity (-LI) level in rat plasma. ET-1-LI was detected in plasma from male Wistar rats. ET-1-LI in rat plasma consisted of three components with molecular weights of 6K, 4K and 2.5K daltons by gel permeation chromatography. Two of the components were eluted at positions of big ET (4K) and synthetic ET-1 (2.5K). The remaining component was eluted at the preceding fraction (6K). No difference was observed in ET-1-LI of the small molecular form of ET (2.5K) between the two RIAs. Thus, there is little or no ET-3 in rat plasma, which has the sequence found originally in the rat genome. The concentration of the small molecular form of ET, presumably ET-1, in rat plasma was about 4 pg/ml.

Animals↗
PubMed1989

Isolation and sequence determination of rat cardiac natriuretic peptide.

We have isolated a cardiac natriuretic peptide of 5K daltons from the rat atrium and determined its amino acid sequence. The 5K cardiac natriuretic peptide was elucidated to be a 45-amino acid peptide with the sequence of S-Q-D-S-A-F-R-I-Q-E-R-L-R-N-S-K-M-A-H-S-S-S-C-F-G-Q-K-I-D-R-I-G-A-V-S-R- L-G-C-D - G-L-R-L-F by sequencing the native peptide and its lysyl endopeptidase digests. The sequence of this peptide was identical to the amino acid sequence [51-95] of the rat brain natriuretic peptide (BNP) precursor deduced from the cDNA sequence. The 5K cardiac natriuretic peptide, or BNP[51-95], was identified as the major storage and secretory form derived from the BNP precursor in the rat heart.

Amino Acid Sequence↗
PubMed1989

Occurrence of a novel cardiac natriuretic peptide in rats.

We established a specific radioimmunoassay for the ring structure of "iso-ANP" and detected iso-ANP[23-46]-like immunoreactivity (-LI) in the rat atrium (2.76 +/- 0.5 micrograms/g) and ventricle (13.9 +/- 5.7 ng/g). High performance-gel permeation chromatography revealed that iso-ANP[23-46]-LI in the rat heart was composed of two components with molecular weights of 10K and 5K. In reverse phase-high performance liquid chromatography, the retention times of these components were clearly different from that of synthetic iso-ANP. The 5K peptide was demonstrated to be present in the perfusate from isolated rat hearts and possessed binding ability to ANP receptors. This natriuretic peptide was, however, not detectable in other tissues including the brain. We conclude that the novel cardiac natriuretic peptide distinct from iso-ANP and ANP occurs in the rat heart and is secreted from the heart.

Amino Acid Sequence↗
PubMed1989

Endothelin in human plasma and culture medium of aortic endothelial cells--detection and characterization with radioimmunoassay using monoclonal antibody.

We have developed monoclonal (KY-ET-1-I) and polyclonal (ET-F5) antibodies against endothelin-1 (ET-1) and established sensitive radioimmunoassays (RIAs) with different specificities. The RIA with KY-ET-1-I detected ET-1, ET-2 and ET-3, while the RIA with ET-F5 recognized ET-3 very weakly. Using these RIAs, we have investigated the concentration and molecular forms of ET-1-like immunoreactivity (-LI) in culture medium of bovine aortic endothelial cells and human plasma. Culture medium of endothelial cells contained two major components compatible with big ET and ET-1. ET-1-LI was also detected in human plasma. ET-1-LI in human plasma consisted of apparent two components, the small molecular form emerging at the position of ET-1 and the large form with the peak eluting at the preceding fraction of the elution position of big ET. The concentration of the small form of ET in human plasma was about 5 pg/ml.

Animals↗
PubMed1989

Brain natriuretic peptide is a novel cardiac hormone.

Using a radioimmunoassay for brain natriuretic peptide (BNP), we have measured levels of BNP-like immunoreactivity (-LI) in extract of the porcine heart, in perfusate from the isolated porcine heart and in porcine plasma. BNP-LI was detected in the extract of the atrium, though no detectable amount of BNP-LI (more than 1 ng/g) was present in the ventricle. The BNP-LI level in the porcine atrium was 148.7 +/- 23.3 ng/g. BNP-LI was also detected in the perfusate from the heart. Basal secretory rate of BNP was 3.18 +/- 0.76 ng/min. Moreover, BNP-LI was detected in porcine plasma at the concentration of 4.2 +/- 1.3 pg/ml. Gel filtration studies showed that BNP is present in the atrium as a large molecule and is secreted into the circulation as a small molecule. The percentage of BNP-LI to atrial natriuretic peptide (ANP)-LI was almost the same among the extract, the perfusate and the plasma (2-3 percent). These results indicate that BNP is synthesized in and is secreted into the circulation from the heat in a similar fashion as ANP.

Animals↗
PubMed1989

Radioimmunoassay for brain natriuretic peptide (BNP) detection of BNP in canine brain.

We established a highly sensitive and specific radioimmunoassay (RIA) for BNP. Our RIA detected BNP-like immunoreactivity (-LI) in the porcine and canine brains but did not detect BNP-LI in the human, monkey or rat brain. The widespread distribution of BNP-LI was demonstrated both in the porcine and canine brains, with the highest concentration in the medulla oblongata. In contrast, the highest concentration of ANP-LI determined simultaneously was in the midbrain and the olfactory bulb. High performance-gel permeation chromatography coupled with RIA revealed that the major component of BNP-LI was eluted at the position of synthetic BNP with a small molecular weight (3K). These results indicate that the RIA for BNP serves as a useful tool to investigate physiological roles of BNP.

Animals↗
PubMed1989

Viremia and neutralizing antibody response in infants with exanthem subitum.

Mononuclear cell-associated viremia caused by human herpesvirus type 6 was detected in 39 (66%) of 59 blood samples from 38 children with exanthem subitum between day 0 and day 7 of the disease. The rate of virus isolation from mononuclear cells was 100% (26/26) on days 0 to 2 (just before appearance of skin rash), 82% (9/11) on day 3, 20% (2/10) on day 4, 7% (2/12) on days 5 to 7, and 0% (0/37) on day 8 and thereafter. The cell-free virus was detected in blood in 10 (21%) of 47 blood samples during the same period. The antibody activity to the virus, evaluated by a newly developed neutralization assay, was first detected on day 3 of the disease with a positive rate of 18% (2/11). It became 60% (6/10) on day 4, 75% (9/12) on days 5 to 7, and 100% on day 8 and thereafter. Thus the disappearance of the virus from blood was associated with the induction of specific immunity to the virus.

Adult↗
PubMed1989

An enzyme immunoassay for K-76 monocarboxylic acid, a novel anticomplementary compound.

A competitive enzyme immunoassay for K-76 monocarboxylic acid (K-76COOH), a novel anticomplementary compound, was developed. K-76COOH was directly coupled with bovine serum albumin through a formation of Schiff base and successive reduction. The spectral data of the conjugate showed no evidence of a Schiff base form. Using the specific antiserum, the proposed homologous assay made it possible to detect K-76COOH at the lowest value of 1 ng/ml of plasma. The immunoassay was validated by the correlation with HPLC analyses. The time courses of plasma levels of K-76COOH after a single oral administration to beagle dogs were precisely determined with a very low absorption efficiency. From these results, it is suggested that the plasma values obtained are insufficient for K-76COOH to exert its anticomplementary action in vivo; thus K-76COOH may have another immunopharmacological function.

Animals↗
PubMed1989

Increased neuropeptide Y concentrations in cerebrospinal fluid from patients with aneurysmal subarachnoid hemorrhage.

We investigated the possible relation between neuropeptides and cerebral vasoconstriction in samples of ventricular or cisternal cerebrospinal fluid from 14 patients with subarachnoid hemorrhage. Neuropeptide Y, calcitonin gene-related peptide, atrial natriuretic peptide, and pituitary polypeptide 7B2 were present in the cerebrospinal fluid of these patients. Concentrations of calcitonin gene-related peptide and 7B2 were not significantly different from those in control subjects, but that of atrial natriuretic peptide was significantly lower. Although the mean concentration of neuropeptide Y was not significantly higher than control, consecutive determinations showed an increase 6-11 days after the onset of subarachnoid hemorrhage. An initially high 7B2 concentration decreased gradually, although half the patients showed a second increase greater than 10 days after the onset. Considering the well-recognized vasoconstrictive effect of neuropeptide Y, it is possible that this increase in its concentration in the cerebrospinal fluid plays a role in the pathogenesis of the cerebral vasospasm that is often seen after subarachnoid hemorrhage.

Aged↗